This experiment was harmless to the animals.

　　這個實驗對動物無害。

　　Not all chemicals normally present in living organisms are harmless.

　　并非所有正常存在于活的有機(jī)體中的化學(xué)物質(zhì)都是無害的。

　　The mountain hasn't been entirely harmless, however.

　　然而，這座山并非完全無害。

　　On their own, cookies are generally harmless, if mildly intrusive.

　　就其本身而言，信息包通常是無害的，即使有輕微的干擾。